ES2637989T3 - Method to prepare a lactate - Google Patents

Abstract

A method for preparing the lactate compound of the following chemical Formula 1, which comprises the step of reacting glycerol with alcohol of the following chemical Formula 2 in the presence of a catalyst, in which the catalyst is a homogeneous or heterogeneous catalyst, in wherein the homogeneous catalyst is at least one selected from the group consisting of an alkali metal compound having a hydroxyl or alkoxy group, a metal compound containing a bicarbonate (HCO3 -), and a metal compound containing a carbonate (CO3 2 -), in which the heterogeneous catalyst is a metal compound containing Mg, Ca, Zr, or Sn or: ** Formula ** in which, R1 is an unsubstituted C1-10 alkyl, a C3-10 cycloalkyl is not substituted, or an unsubstituted C6-10 aryl.

Description

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DESCRIPTION

Method for preparing a lactate Field of the invention

The present invention relates to a method of preparing a lactate compound, which can prepare a lactate compound in high yield.

Background of the invention

Recently, due to the demand for biodiesel, a large amount of glycerol is being produced, and studies on its application have progressed.

Among them, the preparation of lactic acid using glycerol has been suggested. For example, a method of preparing lactic acid from glycerol is known under severe conditions of 300 ° C and 8104 MPa (80 atm) through a hydrothermal reaction using an alkaline base such as NaOH or KOH (Application Publication of United States Patent No. 2009/0088589; United States Patent Application Publication No. 2010/0047140; Ind. Eng. Chem. Res. 2009, 28, 8920; Chemistry Letters 2005, 34, 1560).

However, this method has disadvantages in that an additional process for catalyst separation is required because the catalyst dissolves in the product due to the use of a homogeneous catalyst such as NaOH or KOH, and a large amount is produced of impurities In addition, since the catalyst separation process is very complicated and difficult, the operability is reduced and the process is not economical in terms of costs.

To solve the problems according to the use of a homogeneous catalyst, a method of preparing lactic acid through hydrogenation of glycerol using a heterogeneous catalyst supported on active carbon, such as Pt, Ru, Au. However, this method also has disadvantages because of its low conversion rate and low selectivity (Journal of catalyst 2007, 249, 328; Journal of catalyst 2007, 251, 281).

Meanwhile, in a separator (extraction solution) to remove a photoresist layer in the manufacturing process of fine circuits of integrated semiconductor circuits and liquid display devices, NMP (N-methyl pyrrolidone), DMAc (dimethylacetamide) is generally used as solvent. ), and the like. However, since the solvent is very toxic, lactamide compounds have been used as the solvent that replaces the NMP and the DMAc with their operability and ecology (Korean Patent Publication open for consultation No. 2009-0106992).

The lactamide compound is a low-toxic bio-solvent that respects the environment based on biomass obtainable using glycerol which is a byproduct of biodiesel. Therefore, a method to increase the productivity of lactamide compounds is being studied.

As an existing method of preparing lactamide, a method of preparing lactamide by the reaction of lactic acid and alkyl lactate with amines is known (WO 2009/121488, WO 2009/121489). However, when lactamide is prepared from lactic acid, lactic acid and alkyl lactate are obtained in low yield due to the above problems, and therefore, the yield and purity of lactamide cannot be improved. On the other hand, there is no known method of preparation of alkyl lactate with high yield and high purity.

"Oxidation of glycerol and propane diols in methanol over a heterogenous gold catalyst", Green Chemistry, Vol, 10, No. 4, 2008, pages 408-414, reveals the aerobic oxidation of glycerol on gold nanoparticles supported by metal oxide in methanol

Shipin Keji, 2006,171-173 discloses the synthesis of trilactin from lactic acid and glycerol. Chem. EUR. J., 2007, 13, 4654-4664, discloses the selective esterification of simple 2-hydroxycarboxylic acids.

Detailed description of the invention

Technical problem

The inventors confirmed that if the lactate compound is prepared from glycerol, a catalyst separation process can easily progress, and the conversion rate and selectivity can be greatly improved.

Accordingly, the present invention provides a method for preparing the lactate compound through the dehydrogenation, oxidation and esterification of glycerol and alcohol in the presence of a catalyst.

Technical solution

The present invention provides a method for preparing the lactate compound of the following chemical formula 5, which comprises the step of reacting glycerol with alcohol of the following chemical formula 2 in the presence of a catalyst,

wherein the catalyst is a homogeneous or heterogeneous catalyst,

wherein the homogeneous catalyst is at least one selected from the group consisting of an alkali metal compound having a hydroxyl or alkoxy group, a metal compound containing a bicarbonate (HCO3 "), and a metal compound containing a carbonate ( CO32-),

wherein the heterogeneous catalyst is a metal compound containing Mg, Ca, Zr, or Sn or:

Chemical formula 1

image 1

Chemical formula 2 R1OH

Wherein, R1 is an unsubstituted C1-10 alkyl, an unsubstituted C3-10 cycloalkyl, or an unsubstituted C6-10 aryl.

The present invention will be explained in detail.

The present invention relates to a method of preparing a lactate compound from glycerol. Thus, in accordance with the present invention, the catalyst separation process is simple compared to the existing method even if any of a homogeneous or heterogeneous catalyst is used, and the conversion rate and the selectivity towards the product can be improved. .

In particular, the present invention can prepare the lactate compound using cheap glycerol as a starting material.

The method of the present invention prepares a lactate compound through dehydrogenation, oxidation and esterification, as shown in Formula 1.

25 Reaction formula 1

image2

wherein, R1 is unsubstituted Ci-i0 alkyl, unsubstituted C3-i0 cycloalkyl, or unsubstituted C6-i0 aryl,

As shown in Reaction Formula 1, the present invention provides a method of preparing the

Lactate compound of the following chemical formula 1, comprising the step of reacting glycerol with alcohol of the following chemical formula 2, in the presence of a catalyst:

Chemical formula 1

image3

5 Chemical formula 2 R1OH

wherein, R 1 is an unsubstituted C 1-10 alkyl, an unsubstituted C 3-10 cycloalkyl, or an unsubstituted C 6-10 aryl.

As glycerol, usually available glycerol can be used which is obtained as a biodiesel byproduct.

The alcohol of the chemical formula 2 can be used as a solvent and reagent, and the content can be from about 1 to 50 parts by weight, more preferably from about 1 to 30 parts by weight, more preferably from about 1 to 20 parts by weight. weight, based on 1 part by weight of glycerol. If the content is less than about 1 part by weight, it may be difficult to participate sufficiently in the reaction, and if the content is greater than about 50 parts by weight, the alcohol can increase the reaction pressure.

In addition, R 1 in the alcohol of the chemical Formula 2 may preferably be methyl or ethyl.

The existing method mainly uses water as a solvent, but it was very difficult to separate the lactic acid in the aqueous solution. On the contrary, since the method of preparing the lactate compound of the present invention prepares the lactate compound using alcohol, the catalyst can be easily separated and purified from the product after the reaction is completed, even if the reaction is completed. it uses any of a homogeneous or heterogeneous catalyst, and therefore, a process of separating a catalyst from the product can easily progress. The heterogeneous catalyst can be more advantageous since it can be separated and recycled more easily compared to the homogeneous catalyst.

As a homogeneous catalyst, at least one selected from the group consisting of an alkali metal compound having a hydroxyl group or an alkoxy group, a metal compound containing a bicarbonate (HCO3-), and a metal compound containing a carbonate should be used. (CO32-). The alkali metal compound having a hydroxyl group may include NaOH, KOH, LiOH, Ba (OH) 2, and the like. The alkali metal compound having an alkoxy group may include NaOR, KOR, LiOR, and the like (R is a substituted or unsubstituted Ci-I0 alkyl group). R can be methyl, ethyl, propyl or isopropyl.

As a heterogeneous catalyst, a metal compound containing Mg, Ca, Zr, or Sn should be used.

In addition, the heterogeneous catalyst may be in the form of a complex of the metal compound containing Mg, Ca, Zr, Sn of an oxide form and other materials.

Preferably, the heterogeneous catalyst may also include at least one selected from the group consisting of an alkali metal compound, a metal compound containing a hydroxyl group (OH-), a metal compound containing a bicarbonate (HCO3-), a compound metal containing a carbonate (Co32-), activated clay (acid clay), zeolite, active carbon, diatomaceous earth, bentonite, alumina, silicalite, fly ash, molecular sieves, vermiculite, perlite, compound n adsorbent, clay and 35 polymer resin.

For example, the method for preparing the lactate compound using the heterogeneous catalyst can be advanced using a heterogeneous catalyst of the metal compound containing Mg, Ca, Zr, or Sn, and a basic compound containing a hydroxyl group (OH-), and the use of an alcohol solvent.

The amount of the catalyst is not specifically limited, but preferably it can be from about 40 0.001 to 10 equivalents, more preferably from about 0.01 to 5 equivalents, based on 1

glycerol equivalent.

Also, the reaction to prepare the lactate compound can be carried out in a batch reactor or a tubular reactor.

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The reaction can be carried out at a temperature of about 100 to 300 ° C, preferably about 80 to 250 ° C, and a pressure of about 10,130 to 20,260 MPa (100 to 200 atm) for about 1 to 20 hours in the atmosphere inert. The inert atmosphere refers to common conditions, such as Ar, helium, and the like.

According to the method, the lactate compound can be prepared with a yield of about 50% or higher, preferably a yield of about 70 to 90%, and a selectivity of about 80% or higher. In addition, since the method of the present invention uses alcohol as a solvent, separation and purification are easier compared to the existing method, and therefore, an effective method of preparing the lactate product can be provided.

Advantageous effects

According to the present invention, by preparing a lactate compound from glycerol using a homogeneous or heterogeneous catalyst, an economical preparation method having a high yield and high selectivity can be provided and the catalyst can be easily separated and purified. by using glycerol.

Therefore, since the present invention can replace expensive and toxic existing solvents, NMP, DMAc, it is economical and environmentally friendly. In addition, since the present invention is economically prepared lactate compound which is used as a monomer and raw material for the preparation of polymer, it can contribute greatly to several fields, including a process of preparing electronic material, a coating solvent, a field that respects the environment, and the like.

Examples

Hereinafter, the present invention will be explained in detail with reference to the following Examples. However, these examples serve only to illustrate the invention, and the scope of the invention is not limited to them.

Experimental method

In the following Examples and Comparative Examples, all operations of manipulation of air or water sensitive compounds were carried out using the conventional Schlenk technique or dry box technique.

The conversion rates of the lactate and lactamide compound prepared were measured using GC (gas chromatograph) and HPLC (high performance liquid chromatograph).

Synthesis Example 1: Na / MgO Catalyst]

~ 80-85% by weight of Mg (OH) 2 and ~ 15-20% by weight of NaOH were impregnated at 80 ° C in a carbon dioxide atmosphere, and dried at 125 ° C. Then, the mixture is cooked at 850 ° C for 4 hours, and a Na / MgO catalyst is obtained in a yield of 90%.

Synthesis Example 2: Sn / Zeolite Catalyst

Tetraethylorthosilicate (6 g), tetraethyl orthotitanate (0.5 g), stannous ethoxide (0.5 g) and tetrapropylammonium hydroxide (4 g, 40% by weight) were mixed in a high pressure reactor and the mixture was mixed. stir at room temperature for 1 hour. The alcohol formed was removed by distillation, distilled water was added to the residue, and then the mixture was crystallized at 175 ° C for 24 hours under stirring. Next, the product was obtained by spray drying with a yield of 94% based on SiO2.

Synthesis Example 3: Na / NaOH / AhOa Catalyst]

A ^ O3 (80% by weight) and NaOH (10% by weight) were stirred at ~ 550-600 ° C for 4 hours, Na (10% by weight) was added, and the mixture was stirred for ~ 1-2 hours, and then cooled to room temperature to prepare a catalyst in 85% yield.

Example 1

Preparation of methyl lactate using catalyst 1

Glycerol (1 g), catalyst 1 (0.2 g) and methanol (5 g) were introduced into a 200 ml high pressure reactor under Ar atmosphere, and reacted at 160 ° C and 4052 MPa (40 atm) for 5 hours. Then the mixture

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The reaction mixture was cooled to room temperature and then the methyl lactate was separated by fractional distillation and was obtained in 80% yield.

1H NMR (CDCl3): 5 4.3 (q), 3.79 (s), 2.89 (sa), 1.42 (d)

Example 2

Preparation of methyl lactate using catalyst 2

Glycerol (1 g), catalyst 2 (0.2 g) and methanol (5 g) were introduced into a 200 ml high pressure reactor under Ar atmosphere, and reacted at 160 ° C and 4052 MPa (40 atm) for 5 hours. Then, the reaction mixture was cooled to room temperature, and the methyl lactate was removed by fractional distillation and obtained in a yield of 90%.

1H NMR (CDCb): 5 4.3 (q), 3.79 (s), 2.89 (sa), 1.42 (d)

Example 3

Preparation of methyl lactate using catalyst 3

Glycerol (1 g), catalyst 3 (0.2 g) and methanol (5 g) were introduced into a 200 ml high pressure reactor under Ar atmosphere, and reacted at 160 ° C and 4052 MPa (40 atm) for 5 hours. Then, the reaction mixture was cooled to room temperature, and the methyl lactate was removed by fractional distillation and was obtained in 85% yield.

1H NMR (CDCla): 5 4.3 (q), 3.79 (s), 2.89 (sa), 1.42 (d)

Example 4

Preparation of methyl lactate using MgO

Glycerol (1 g), methanol (5 g) and MgO (0.2 g) and NaOH (0.5 g) were introduced as catalyst in a 200 ml high pressure reactor under Ar atmosphere, and reacted at 160 ° C and 4052 MPa (40 atm) for 5 hours. TO

then, the reaction mixture was cooled to room temperature, and the methyl lactate was distilled off

fractionated and was obtained with a yield of 93%.

1H NMR (CDCla): 5 4.3 (q), 3.79 (s), 2.89 (sa), 1.42 (d)

Example 5

Preparation of methyl lactate using CaO

Glycerol (1 g), methanol (5 g) and CaO (0.2 g) and NaOH (0.5 g) were introduced as catalyst in a high reactor

200 ml pressure under Ar atmosphere, and reacted at 160 ° C and 4052 MPa (40 atm) for 5 hours. TO

Then, the reaction mixture was cooled to room temperature, and the methyl lactate was removed by fractional distillation and obtained in a yield of 90%.

1H NMR (CDCls): 5 4.3 (q), 3.79 (s), 2.89 (sa), 1.42 (d)

Example 6

Preparation of methyl lactate using ZnO

Glycerol (1 g), methanol (5 g), and ZnO (0.2 g) and NaOH (0.5 g) were introduced as a catalyst in a high reactor

200 ml pressure under Ar atmosphere, and reacted at 160 ° C and 4052 MPa (40 atm) for 5 hours. TO

Then, the reaction mixture was cooled to room temperature, and the methyl lactate was removed by fractional distillation and was obtained in 88% yield.

1H NMR (CDCls): 5 4.3 (q), 3.79 (s), 2.89 (sa), 1.42 (d)

Example 7

Preparation of ethyl lactate using MgO

Glycerol (1 g), ethanol (5 g) and MgO (0.2 g) and NaOH (0.5 g) were introduced as catalyst in a 200 ml high pressure reactor under Ar atmosphere, and reacted at 160 ° C and 4052 MPa (40 atm) for 5 hours. TO

Then, the reaction mixture was cooled to room temperature, and the ethyl lactate was distilled off.

fractionated and was obtained with a yield of 90%.

1 H NMR (CDCls): 5 4.3 (q), 4.19 (q), 2.89 (sa), 1.42 (d), 1.33 (t)

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Example 8

Methyl lactate is prepared in 73% yield by the same method as in Example 1, except that NaOMe (0.5 g) was used as catalyst.

1H NMR (CDCl3): 5 4.3 (q), 3.79 (s), 2.89 (sa), 1.42 (d)

Example 9

Methyl lactate is prepared in 65% yield by the same method as in Example 1, except that NaOH (0.5 g) and H 2 O (0.1 g) was used as catalyst.

1H NMR (CDCl3): 5 4.3 (q), 3.79 (s), 2.89 (sa), 1.42 (d)

Comparative Example 1

Using 2 ml of NaOH (1.5 M) as catalyst and 2 ml of glycerol, a hydrothermal reaction was carried out under severe conditions of 300 ° C, 9117 MPa (90 atm), and the neutralization reaction was carried out. with H2SO4, and then, lactic acid was prepared in an aqueous solution with 58% yield. Lactic acid production was confirmed by LC (liquid chromatograph).

Claims (6)

5 10 fifteen twenty 25 1. A method for preparing the lactate compound of the following chemical formula 1, which comprises the step of reacting glycerol with alcohol of the following chemical formula 2 in the presence of a catalyst, wherein the catalyst is a homogeneous or heterogeneous catalyst, wherein the homogeneous catalyst is at least one selected from the group consisting of an alkali metal compound having a hydroxyl or alkoxy group, a metal compound containing a bicarbonate (HCO3 "), and a metal compound containing a carbonate (CO32 -), wherein the heterogeneous catalyst is a metal compound containing Mg, Ca, Zr, or Sn or: Chemical formula 1 image 1 Chemical formula 2 R1OH wherein, R1 is an unsubstituted C-mo alkyl, an unsubstituted C3-1o cycloalkyl, or an unsubstituted C6-I0 aryl. 2. The method according to claim 1, wherein the alkali metal compound having a hydroxyl group is NaOH or KOH, LiOH or Ba (OH) 2, and The alkali metal compound having an alkoxy group is NaOR, KOR or LiOR, wherein R is a substituted or unsubstituted C1-10 alkyl group. 3. The method according to claim 1, wherein the heterogeneous catalyst further comprises at least one selected from the group consisting of an alkali metal compound, a compound containing hydroxyl metal groups, a metal compound containing bicarbonate, a metal compound containing carbonate, activated clay, zeolite, active carbon, diatomaceous earth, bentonite, alumina, silicalite, fly ash, molecular sieves, vermiculite, perlite, complex n compound adsorbent, clay and polymer resin. 4. The method according to claim 1, characterized in that the reaction is carried out in a batch reactor or a tubular reactor. 5. The method according to claim 1, characterized in that the reaction is carried out at a temperature of 100 to 300 ° C and a pressure of 1013 to 20,265 MPa (10 to 200 atm) for 1 to 20 hours, under an inert atmosphere . 6. The method according to claim 1, wherein R1 in the alcohol of chemical formula 2 is methyl or ethyl.